This is a Cancer Center grant which is currently supporting basic research in areas of molecular and cellular biology which directly relate to the ways in which viruses change normal cells into cancer cells. There is close working together of several major research divisions: (1) Tumor Virus Section, (2) Cell Culture and Virus Preparation Section, (3) Protein Synthesis Section, (4) Mammalian Cell Genetics Section, (5) Cell Biology Section, (6) Electron Microscopy Section, (7) Nucleic Acid Chemistry Section, (8) Molecular Genetics Section, (9) Central Research Services Section, (10) Meetings and Immunogenetics Workshop Section. This supplement requests funds for the addition of a Protein Chemistry Section.